How can I change the style of a UIBarButtonItem in code

Question

I am using UIBarButtonSystemItemPlay to play my audio file and I want to dynamically change its style when I click it. Is this possible? If yes, then please help me. This is my code where _playPause is the IBOutlet UIBarButtonSystemItemPlay. Thanks in advance.

- (IBAction)playPause:(UIBarButtonItem *) sender { if (_playPause.style == UIBarButtonSystemItemPlay) { [_playPause setStyle:UIBarButtonSystemItemPause]; [audio play]; } else { [_playPause setStyle:UIBarButtonSystemItemPlay]; [audio pause]; } } 

Answer 1

UIBarButtonSystemItemPlay or UIBarButtonSystemItemPause cannot be restored using the style property. the style is of type UIBarButtonItemStyle .

Check out the documentation here .

I suggest creating two different UIBarButtonItem and then turning them on or off alternately (for example). You can also delete the current visible button and add a new one with another UIBarButtonSystemItem .

Answer 2

Here is a fairly complete solution for this that I just implemented:

Define vars first to hold both buttons:

 @property (weak, nonatomic) IBOutlet UIToolbar *toolbar; @property (strong, nonatomic) IBOutlet UIBarButtonItem *playButton; @property (strong, nonatomic) IBOutlet UIBarButtonItem *pauseButton; 

(I understand that the toolbar is a weak ref, because it is defined through IB, and it has a strong pointer to it, but the play / pause buttons are strong pointers, because we create them below. Fu is a little weak on this front as a pretty newbie , so the fixes were appreciated.)

Secondly, in IB, create a play button (without a pause button) and bind it to the previous version of playButton var.

Third, configure this method:

 - (void) setAsPlaying:(BOOL)isPlaying { self.rootViewController.playing = isPlaying; // we need to change which of play/pause buttons are showing, if the one to // reverse current action isn't showing if ((isPlaying && !self.pauseButton) || (!isPlaying && !self.playButton)) { UIBarButtonItem *buttonToRemove = nil; UIBarButtonItem *buttonToAdd = nil; if (isPlaying) { buttonToRemove = self.playButton; self.playButton = nil; self.pauseButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemPause target:self action:@selector(pauseAudio:)]; buttonToAdd = self.pauseButton; } else { buttonToRemove = self.pauseButton; self.pauseButton = nil; self.playButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemPlay target:self action:@selector(playAudio:)]; buttonToAdd = self.playButton; } // Get the reference to the current toolbar buttons NSMutableArray *toolbarButtons = [[self.toolbar items] mutableCopy]; // Remove a button from the toolbar and add the other one if (buttonToRemove) [toolbarButtons removeObject:buttonToRemove]; if (![toolbarButtons containsObject:buttonToAdd]) [toolbarButtons insertObject:buttonToAdd atIndex:2]; // vary this index to put in diff spots in toolbar [self.toolbar setItems:toolbarButtons]; } } 

Fourth, call setAsPlaying wherever you are going to play or in pause mode. For example:

 -(IBAction) playAudio:(id)sender { [self.audioPlayer play]; [self setAsPlaying:YES]; } -(IBAction) pauseAudio:(id)sender { [self.audioPlayer pause]; [self setAsPlaying:NO]; } 

Answer 3

I believe that as soon as the style is installed initially (i.e. in the interface builder or when creating a button in the code), you cannot change it.

The only other option is to remove the button in the code and create a new one in its place using a different style. You can call this method:

 - (id)initWithTitle:(NSString *)title style:(UIBarButtonItemStyle)style target:(id)target action:(SEL)action 

For more on UIBarButtonItem see this .

Answer 4

Yes, you cannot change the “style” (it is not called the actual style) after installing it.

Yes, you can make another button that fixes it.

Here is the reuse code that does this:

 UIBarButtonItem *newButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:controller.navigationItem.rightBarButtonItem.target action:controller.navigationItem.rightBarButtonItem.action]; controller.navigationItem.rightBarButtonItem = newButton; 

This is usually a self controller.